Bedbugs don't mind sleeping with their sisters and brothers, if you know what I mean.

And bedbugs' eagerness to mate with their kin is one reason their populations have taken off so dramatically. Inbreeding comes naturally to them, and it doesn't seem to hurt their offspring much, as is the case with most other creatures.

"When we look at the genetic makeup of an apartment building, we found that most of the time, the bugs are all related to each other," entomologist Coby Schal tells Shots. "That suggests that there is a lot of inbreeding occurring."

He and another entomologist named Ed Vargo examined genetic markers of apartment-dwelling bedbugs in New Jersey and North Carolina. They found remarkable genetic similarities among bedbugs living under one roof.

Schal says all it takes is one mated female to check into a room for the bedbug party to get started. Once her sons and daughters become adults --about 35 days — they will mate with each other. Their offspring will repeat the cycle and so on.

"Inbreeding allows bedbugs to establish a large population with a small start," Schal says. The amount of genetic similarity among the offspring suggests that outside bugs are rarely getting in on the action.

The good news is that bedbugs' incestuous ways can help people cut off a looming invasion. Since most infestations start with only one or two bugs, Schal says, "if you detect them early and get rid of them, chances are you won't see another infestation for a while."

One look at a list of the most infested areas shows that bedbugs love the city life.

So, where are these itchy individuals coming from? Turns out, when Schal and Vargo looked at bedbug populations across the country, they found large amounts of genetic diversity among locations.

Most likely, this means bugs from various places around the globe started new colonies in different buildings. For example, one apartment complex may house a line of descendants from Betty the bug, but down the street another apartment may have a line of progeny started by Barbara.

Betty may have been smuggled into her building on a used couch. Barbara may have hitched a ride on a jet-settter's luggage.

Next up for Schal is finding where bedbug population originated. "We want to identify where the ancestral population coming from," he says. "Where's Eve? And from a mechanistic perspective, how can bedbugs withstand the detrimental effects of inbreeding that other animals can't."